1. Field of the Invention
The present invention relates to a display unit to be provided for mobile apparatuses such as a portable telephone, a notebook-sized personal computer (PC), a mobile information terminal device or the like, more particularly to a display unit and a mobile apparatus using the display unit, and more particularly to a display unit in which a display device and a thin secondary battery are integrally combined to form a module structure, and to a mobile apparatus into which the display device is assembled.
2. Description of the Related Art
As the mobile apparatuses such as the portable telephone, notebook-sized personal computer (PC) or the like have rapidly become popular, a miniaturization of the mobile apparatuses has been advanced, so that there is a tendency that parts to be assembled are made compact and the parts are replaced by semiconductor elements, while a size of a display device as a liquid crystal cell has been enlarged in view of legibleness and clear observation for the display device.
Further, as the mobile apparatuses have rapidly become popular, a demand for secondary battery as a power source for the apparatus has also been rapidly increased. To make the second battery compact and thin in thickness and to have a light weight and high capacity has been also demanded, and the thin-type secondary batteries have been developed for realizing the compactness and light weight of the mobile apparatuses.
In particular, the mobile apparatuses are strongly demanded to be made compact and thin in thickness in view of good portability (mobility) in addition to an improvement in functions thereof, so that the secondary battery as unit power source is also demanded to be made to have thin size, light weight and long-life characteristic. While, the display device is demanded to enlarge the display screen in view of legibleness even if the entire mobile apparatus is made compact to have the light weight.
In accordance with that the mobile apparatuses are made compact to have the light weight, the display device provided to the mobile apparatus is also required to be made compact and thin to have light weight. However, the display screen of the display device is required to enlarge a size of the display screen in view of legibleness. On the other hand, it has been known that the display device to be assembled into the display unit has a weak resistance to heat or stress due to display materials such as liquid crystal or the like and structural factors of the display device.
In addition, the secondary battery assembled into the mobile apparatus causes a heat generation during the charging/discharging operations.
Therefore, the display device and the secondary battery mutually have characteristics exactly opposing to each other. In this regard, it has been generally considered to be difficult to combine the display device with the secondary battery so as to integrate each other for the purpose of making the mobile apparatus compact to obtain a light weight i.e., for the purpose of making the display device compact and thin to provide light weight.
In actual, the display device such as liquid crystal cell or the like is weak against heat or stress, and the function of the liquid crystal material is greatly lowered by the heat generated during the charging/discharging operation of the secondary battery, so that there has been posed a problem that the displaying function of the display device is damaged and lost.